The leads of electronic components are tinned prior to use and soldering. Integrated circuits are normally assembled with pretinned leads. The leads are tinned by applying a flux coating to the leads, drying the coating, applying molten solder to the flux-coated leads, and cleaning the coated tinned leads to remove excess flux.
Properly tinned leads are essential for the formation of a good solder joint between the lead and a connecting conductor. Tinned leads after a period of time, such as six months, develop an oxide coating and/or coating from other contaminants that interfere with the formation of a good solder joint. As a result, for high-quality electronic devices the leads of all electronic components utilized in the devices must be freshly tinned. This requirement has compelled the electronic industry to date-control their electronic component inventory and to junk, degrade or re-tin electronic components prior to assembly. The retinning operation has been primarily a hand operation because there are not many suitable or affordable tinning machines on the market.
The present invention is directed to a tinning apparatus that can be used to tin and re-tin a plurality of electronic components at one time, that is, tin and/or re-tin the leads of electronic components. The device of the present invention automatically fluxes, dries the flux coating and tins the leads of a plurality of electronic components at one time. In addition, if something goes wrong during the operation the operation can be promptly aborted. The process and device can be used for original tinning or retinning. For retinning, the tinned lead is fluxed (frequently with a flux compounded for retinning), the flux coating is dried and the fluxed lead is retinned with molten solder.